Right now I've modified this code
<meta name="description" content="<?php echo htmlspecialchars($this->getDescription()) ?>" /> to be this code
<meta name="description" content="<?php echo strip_tags($this->getDescription()) ?>" /> and all the horrible html has been stripped from my meta descriptions that are auto generated from the description if left empty. Any idea how I could modify this to remove and replace it with a space as well?
str_replace(' ', ' ', $this->getDescription()) will return another string with replaced with a space. This means you can just replace $this->getDescription() (which returns a string) with the str_replace() function:
<meta name="description" content="<?php echo strip_tags(str_replace(' ', ' ', $this->getDescription())) ?>" /> It could be a little cleaner if you break it up:
<?php $description = $this->getDescription(); $description = strip_tags($description); $description = str_replace(' ', ' ', $description); ?> <meta name="description" content="<?=$description?>" /> Note <?=$description?> is shorthand for <?php echo $description; ?>.
I think the correct approach is to fix the source data. You can do that in the Magento backend or update data directly in the database (db table catalog_product_entity_text, you need to find out correct attribute_id from eav_attribute db table).
Take a look @ How to remove html special chars?
$description = preg_replace("/&#?[a-z0-9]+;/i","", $description); 
and replace with ` `str_replace(' ', ' ', $this->getDescription());